Join Date: Jan 2016
Location: Shiawassee County, MI
Yes, Swede case head is a bit bigger. 6.5 x 55 SAAMI rim is .4803" and case head is .4782". All of my current batch of case rims measure .477- .478" except for Winchester cases which measure .474. 7 x 57 SAAMI rim is .473" and case head is .471.
From earlier reloading for another 6.5 x 55 I recall that the Winchester case rims/heads were smaller than European brands.
6.5 x 55 SAAMI chamber diameter is .4794 at the chamber mouth. My fired cases are typically .478" at the web regardless of brand. Unfired Lapua cases are .473" at the web, fired Lapua cases are .480" at the web ring. Fired case web at .480" doesn't make sense for a .4794" chamber mouth. My neck sized one fired case reloads seemed to chamber OK.
I think next step will be to pull the barrel and measure chamber mouth diameter and perhaps make a chamber cast to determine chamber diameter at case web depth.
Last edited by M134 Troll; 01-12-2020 at 06:07 PM.